Spray drying apparatus for liquid material



Feb. 10, 1959 G. J. NIEUWE-NHUIS ET AL SPRAY DRYING APPARATUS FOR LIQUIDMATERIAL Filed Sept. 19, 1955 2 Sheets-Sheet 1 JNVENTORS Charles CHarrison a Gurmr J. Nieuwenhuis M,M M'

Feb. 10, 1959 G. J. NIEUWENHUIS ETAL 2,872,973

SPRAY DRYING APPARATUS FOR LIQUID MATERIAL Filed Sept. 19. 1955INVENTORS Charles C.Hc\rrison 8\ Gurmt J. Nieuwenhuis AttorneysSPRAYDRYING APPARATUS FOR'LIQUID 1 MATERIAL V Garmt .7. Nieuwenhuis andCharles C. Harrison,

Seattle, Wash. Y I

The present invention relates to methodandapparatus for drying liquidmateriahfian'd has particularapplication in the .drying of animal blood.Accordingly, the ,invention willbe described with reference to theprocessing of blood, but no' limitation in the use of the invention forthis one liquid material is intended. p f

In the prior art a stream of heated air has been commonly employed asthe sole means to dry animal blood sprayed into the stream. Theresult-ing apparatus has not been particularly eflicient and has beennecessarily large insize and too costly for employment in relativelysmall slaughtering establishments. Therefore, thepresent invention aimsto provide an improved drying method which utilizes extremely compactimproved apparatus which is of economical construction and simple tooperate. In carrying outthis object we apply heatdi'rectly to the animalblood while it is sprayed as well as heating air passed through'thespray, which air, asv above-mentioned, has heretofore been relied "uponas the sole heat source for the sprayed blood. 2

As a further object we aim .to provide an improved spraying assembly inthe drying apparatus.

With yet additional. objects and advantages view which, with theforegoingwill appear and be understood in the course of the followingdescription and .claims, the invention consists in the new method and inthe apparatus for performingsaid method, and in the adaptation andcombination of parts hereinafterdescribed .and claimed.

In the accompanying drawings: Figure 1 is a sideelevational view, partlyin vertical section, ofour improved drying apparatus.

Fig. 2 is a fragmentary longitudinal vertical sectional view through ourimproved spraying assembly takenas indicated by line;22 of Fig. 1. YFig. 3 is a transverse fragmentary sectional view of the spray headtakenas shown by line 3- 3 .in Fig. 2. Fig. 4 is a top plan view of ourapparatus; p Fig. 5 is a fragmentary transversevertical sectional viewthrough "one of the burner units and taken as indicated by line 5-5 inFig. 4. i i

Fig. 6 is a fragmentary longitudinal sectionaltview taken as indicatedby line 6-6 in Fig. 5; and

Fig.7 is -a side elevational view of& modified housing providing thedrying chamber. I

Referring to the drawings it is seen that a drying chamher is providedby a cylindrcal housng 10 fabrcated from sheet metal and havng top andbottom walls 1 1, 12. .The housng may be externally insulated if desiredand its side wall has anaccess door 13 and glass-covered peep hole 14.At its center the top wall 11 is formed with an opening through which issuspended a well-defining menimm the resulting well is a sprayingassembly which infcludes a disc-like spray head 18 located below themember 15.

This spray head 18 is wedged'onto 'a'tape'red section 19 formed at theends of a tubular member 24. The inner races of the units are heldagainst respective of annular shoulders 25 by nuts 26 each having alocking comple ment 27. Defined between the bearing units is alubricating chamber. Oil vapor for lubricating the bearings is suppliedto this chamber through a tube 28 connecting .by an elbow fitting 29with the tubular member 24.

A cap 30 secured by screws 31 closes the upper end of the member 24 andhas a center opening through which the shaft 20 projects upwardly toreceive a pulley 32. This pulley is sleeved on a terminal neck and isheld rigidly with respect to the shaft by a nut 33. A belt 34 transferspower to the pulley 32 from a drive pulley 35 located on the verticallyarranged output shaft of an electric motor 36. The latter is secured toan angle bracket 37 which is mounted on the top wall 11. It is from thisbracket that the yoke armsll' extend, first horizontally, and thendownwardly to connect with a semicylindrical clamp half 38, the otherhalf 39 of the clamp being shorter and secured directly to the tubularmember 24. Opposed perforated ears project laterally from the verticalside edges of these clamping complements 38, 39 to receive bolts 40 fordrawing them together.

. The spray head 18 has a cavity 41 open at the top except for aninturned peripheralflange 42. Depending into the cavity and closing thelower end of the tubular member 24 is a circular manifold member 43.This member has a downwardly faced annular groove 44 which is covered bya round plate 45. Several holes 46 in this plate connect the groove withthe cavity and screws 47 hold the plate and manifold member 43 inposition.

. It will be noted that the latter presents a rim flange 48 closelyoverlying the flange 42, but not in contact there with.

Radiating horizontally from the cavity 41 are a plurality of evenlyspaced discharge passages 49. These passages are purposely elongated andare not truly radial, but as shown in Fig. 3, make approximately aforty-five degree angle with respective .radii through their innerends.. The animal blood or other liquid material to be dried is pumpedthrough a supply tube 50 leading into the annular groove 44. From thenceit travels through the holes 46 into the cavity 41 of the rotating sprayhead wherein centrifugal force urges the blood radially outward into thedischarge passages 49 from which it issues in spray form. The purpose ofelongating the discharge passages 49 is'to assure that the blood willgain the peber 15 having an inverted frustro-conical shape and an uppersupport rim 16. Depending from yoke arms .17

such axes.

ripheral speed of the spray head before discharging therefrom; In thisregard these passages 49 digress from 'a radius as afore-mentioned inthe direction of rotation of the spray head so that the individual bloodparticles will have a resultant direction of travel as they move fromthe spray head which forms as small an acute angle as practical with atangent passing through the outer end of the respective dischrgepassage. In other words we desire the sprayed blood to leave therotating spray head in as close to a tangential pathas possible. Spacedequidistantly from the spray assembly area plurality of direct heatsources, shown for purposes of example as being elongated gas burnerunits '51. These units extend horizontally and depend into rectangularradial cutouts 52 formed in the top wall 11 and serving as inlets to thedrying chamber. As best shown in Fig. 5, the burners are tilted abouttheir longitudinal axes so that their jet passages .53 leading todiffuser screens 54 are about thirty degrees 'from a vertical planethrough Accordingly, the flame fronts of the burners are tilted acorresponding amount from the vertical and the direction of tilt thereofshould be in correspondence with the direction of rotation of the sprayhead. The hollow body section 55 of each burner unit has inner and outerend flanges 56, 57 to which are bolted caps 58, 59. Cap 58 threadablyreceives an elbow 60 which joins a vertical leg of a respectiveT-fitting 61. The arms of the latter are joined by arcuate manifold pipesections 62 to form a circular manifold which may be supported from theoverhead or by brackets mounted on the top wall 11. A pipe 63 suppliesgas to the manifold and hence to the burners.

It should be noted from Fig. that the body section 55 of each burner isspaced from the side edges of the respective cutout 52 so that thecutout can serve as an air inlet to the drying chamber as well asaccommodating the burner. Also, it should be observed that the bodysection 55 has flat sides 64 making the body section a diverter tendingto guide air entering the cutout in the same general direction as theflame front of the burner.

Air is caused to be fed from the atmosphere into the housing through theinlets 52 by a blower 65 which draws air from the drying chamber via anoutlet duct 66 joining the center of the bottom wall 12. As the airtravels the length of the housing from the inlets to the outlet ittravels a generally cycloidal or whirl path because of the tilted flamefront and diverter effect of the burner units 51, the circularcross-section of the housing I 10, and the central location of theoutlet. The direction of rotation of this cycloidal path is the same asthat of the spray head 18.

Reviewing the operation of our drying apparatus it should be kept inmind that the burners 51 have two particular heating functions, andnamely to heat the air immediately upon its entry through the inlets 52and to apply heat directly to the liquid material to be dried as it issprayed in the general direction of the flame fronts of the burners bythe spray head 18. The heated air aids in the drying of the material,absorbs the moisture yielded by the material, and serves to carry thedried material from the drying chamber. After passing out of the latterand through the blower 65 the dried material is centrifuged from its aircarrier by a cyclone separator in the conventional manner. It should bekept in mind that the swirl of the centrifugalized liquid to be dried asit issues from the spray head will approximate directionally the swirlof the heated air in the drying chamber so that the sprayed liquidmaterial will have substantially no tendency to disrupt the cycloidaltravel path of this air as the air and material merge.

As an example of operation conditions for the drying of animal blood byour method and apparatus, dried blood which is 80% soluble and has amoisture content of 8 to 10% can be obtained when the air is drawnthrough the blower at 2,000 cu. ft./min., the liquid bloodis sprayed at80 -gal./hr., and the outlet temperature is about 375 F. before sprayinghas commenced. Raising of this temperature causes a reduction in thesolubility and moisture content of the dried blood. In all cases theliquid blood should be well filtered before being fed to the sprayassembly.

The quantity of air required of course may be affected by atmosphericconditions if the air is drawn directly from the atmosphere into thedrying chamber in that on a highly humid day a greater air flow would berequired to absorb a given amount ofmoisture yielded by the liquid whiledrying than on a day of low humidity. Accordingly, it is anticipatedthat in some installations it may be desirable to pretreat the air orother gas used to hold its humidity ata constant intake value.

We have illustrated a modified housing 10a in Fig. 7 having a relativelyshort cylindrical head section 66 joined by ring flanges 67 with aconical foot section 68 4 tapering to an outlet. In such an arrangementthe spray head operates in the head section.

In the embodiment illustrated in the drawings gas burners of aparticular type have been disclosed as direct heat sources for purposesof example only since it is not our intention to limit the practice ofour invention to such type or to sources which are gas fired.

The advantages of the invention, it.is thought, will have been clearlyunderstood from the foregoing detailed description. Minor changes willsuggest themselves and may be resorted to without departing from thespirit of the invention, wherefore it is our intention that nolimitations be implied and that the hereto annexed claims be given ascope fully commensurate with the broadest interpretation to which theemployed language admits.

'What we claim is:

1. In drying apparatus, a housing providing a circular drying chamberhaving a longitudinal center axis extending between an inlet end walland an outlet, said end wall having a plurality of air inlet openingstherethrough spaced radially from said axis, a blower having its suctionside communicating with said chamber outlet for drawing air through saidinlet openings and thence in a travel path through said chamber, airdiverter means oper'atively associated with said end wall for impartinga whirl to said travel path, fuel introducing means located in saidinlet openings and producing flame fronts firing directly into saidchamber, centrifugal spray means mounted proximal said end wall forrotation about said axis and operative to spray the material to be driedinto said air travel path proximal said flame fronts whereby moisture inthe sprayed material is absorbed by said air and the dried materialthereupon drawn from the chamber with the saturated air by said blower.

2. In drying apparatus, a houing providing a circular drying chamberhaving a longitudinal center axis extending between an inlet end walland an outlet, said end wall having a plurality of air inlet openingstherethrough equally spaced apart in a circular pattern centered at saidaxis, a blower having its suction side communicating with said chamberoutlet for drawing air through said inlet openings and thence throughsaid chamber, fuel introducing means in said inlet openings andproducing flame fronts firing directly into said chamber with such flamefronts tilted in a common circumferential direction at an acute anglewith respect to a plane transverse to said axis, said fuel introducingmeans thereby causing said air to travel through said chamber in a whirlpath having its axis-generally coinciding with said longitudinal axis,and centrifugal spray means mounted proximal said end wall for rotationabout said longitudinal axis and operative to spray the material to bedried into said air whirl path proximal said flame fronts wherebymoisture in the sprayed material is absorbed by said air and the driedmaterial thereupon drawn from the chamber with the saturated air by saidblower.

3. In drying apparatus, a housing providing a circular drying chamberhaving a longitudinal center axis extendingbetween an inlet end wall andan outlet, said end wall havinga plurality of air inlet openingstherethrough spaced radially from said axis, a blower having its suctionside communicating with said chamber outlet for drawing air through saidinlet openings and thence in a 5 air and the dried material thereupondrawn from the chamber with the saturated air by said blower.

4. In drying apparatus, a housing providing a circular drying chamberhaving a longitudinal center axis extending between an inlet end walland an outlet, said end wall having a plurality of elongated air inletopenings therethrough radiating from said axis in spaced relationthereto, a blower having its suction side communicating with saidchamber outlet for drawing air through said inlet openings and thencethrough said chamber, respective elongated combination fuel introducingand air diverter means located in said inlet openings in spaced relationto most of the length of the longitudinal side edges thereof andproducing flame fronts firing directly into said chamber, said means andflame fronts being so tilted in a common circumferential direction withrespect to a plane transverse to said axis as to cause said air to havea whirling travel path through saidchamber, and centrifugal spray meansmounted proximal said end wall for 6 rotation about said longitudinalaxis and operative to spray the material to be dried into said airtravel path adjacent said flame fronts whereby moisture in the sprayedmaterial is absorbed by said air and the dried material thereupon drawnfrom the chamber with the saturated air by said blower.

References Cited in the file of this patent UNITED STATES PATENTS1,313,779 Bell Aug. 19, 1919 1,471,765 Wilson Oct. 23, 1923 1,782,822Hechenbleikner Nov. 25, 1930 1,853,682 Hechenbleikner Apr. 12, 19322,317,479 Peebles Apr. 27, 1943 2,602,002 Schutt July 1, 1952 2,644,516Brendel July 7, 1953 FOREIGN PATENTS 635,176 Germany Sept. 11, 1936406,100 Italy Oct. 16, 1943

